Artificial leg



ERICKSON ARTIFICIAhLEG Filed Aug. 1940 2 sheets-She 1 //YVENTOg 0 H fe/cxso v 2: v H/s Arrow/Eva o. H. ERICKSON' 2,282,952

ARTIFICIAL LEG Filed Aug -3, 1940 1 '2 Sheets-Sheet 2 I V 7 7 ll'lllll lllln I'IIIIIIIIIIIIIIIA //vvE/vro2 0770 H. fR/CKSON Patented May 12, 1942 UNITED STATES PATENT OFFICE ARTIFICIAL LEG Otto H. Erickson, Minneapolia Minn.

Application August 3, 1940, Serial No. 350,960

1 Claim.

iting the swinging movement of the lower leg section, and to a lock device whereby, under certain conditions, the lower leg section may be locked against pivotal movement in respect to the upper leg section. In addition to these improved functions the invention has for its object a structure in which the leg sections will be asfreeas possible from openings or external notches or joints that are liable to produce a pinching action.

A commercial form of the invention is illustratedin the accompanying drawings wherein like characters indicate like parts throughout the several views.

Referring to the drawings:

Fig. 1 is a view in front elevation showing the improved leg;

Fig. 2 is a side elevation of the improved leg with some parts broken away and some parts sectioned;

Fig. 3 is a side elevation withsome parts broken away and some parts sectioned showing the knee joint structure in the same position as shown in Fig. 2; I

Fig. 4 is a section taken on the line 4-4 of Fig. 1, some parts being broken away;

Fig. 5 is a section taken on theline 5-5 of Fig. '2;

Fig. 6 is a horizontal section taken on the line 66 of Fig. 4; and

Fig. '7 is an enlarged view showing parts found in the vicinity of. the line marked 1-! on Fig. 2,

some parts being shown in full and the position 45 transversely-through the slot 23 and through the of the said parts in the lower leg and foot structure being indicated by dotted lines.

The main elements of the complete leg are the upper leg section II), the lower leg section H, and the foot I2. The upper leg section I0, as usual, is hollowed out to form a socket to receive the upper leg amputation. The lower leg section H is also hollowed out to make it light, but at its lower end has a solid portion I3 to which the foot I2 is pivoted by means hereinafter to be described. The lower end of the upper leg section I is solid but narrowed up to form a strong segmental hub flange I4 so that it will go within the side flanges of the lower' leg section II and is adapted to be pivoted or hingedly connected to said lower leg section.

20 the sides of the lower 'leg section I I.

The leg sections and the foot may be made ,of any suitable material, but preferably are made of wood hollowed or dug out to form strong but comparatively light shells.

The kneejoint pivot, betweenthe saidhub flange I4 and the sides of the lower leg section II, is made by a metal sleeve or bushing I5 and a metallic hinge bolt I6.- The sleeve I5 is tightly driven into the hole bored in the hub flange I l 1 and it is further anchored therein by suitable means such as nut-equipped-e'ye bolts ILapplied as best shown in Figs. 4 and '5, with the nuts of the said bolts countersunk into recesses of the said hub flange. The hinge bolt I6 is passed through the sleeve or bushing I5 with clearance.

so that wire-like rollers I8 are interposed :be--

tween said bolt and sleeve. The ends of the bolts I6 are passed through the ends of metallic straps I9 that are riveted or otherwise rigidly secured to Atone end hinge bolt I6 is shown as provided with a head that has threaded engagement with the adjacent strap I9, but at its other end said ,bolt is shown as provided with a head-forming screw that clamps theopposite hinge strap I9. Also, pref erably, and as shown, the bolt I6 is formed with oil-containing grooves 2I adapted to contain a limited amount of oil or grease for delivery to the rollers I8. On the ends. of the knee hinge bolt I6, between the upper ends of the straps I9 and the ends of the sleeve I5, are looselyjournalled small sheaves or grooved wheels 22.

Theelements of the preferred form of the knee hinge connection between the upper and lower leg sections have now been described. For limit- '40 preferred arrangement, is accomplished by providing the hub flange I4 with a segmental-slot 23 that is concentric to' the axis of the hinge bolt I6. For cooperation with the slot 23, I employ a simple stop bolt or rod 24-that extends hinge straps I9, and is anchored to the latter. This stop bolt may be applied invarious ways,

but preferably and as shown, at one end is pro- Y vided with a head ZE that has threaded engageb0 ment with the adjacent strap I9, and at its other end is provided with a head-forming screw 26 that engages the other strap I9. With this ar-, rangement, both the hinge bolts I6 and the stop bolt or rod 24 are anchored to the metallic straps I9, which in turn are rigidly secured to the lower leg section. Journalled on the ends of the stop bolt 24, between the straps I9 and the sides of the hub flange I4, are small sheaves or grooved wheels 21.

Legs of the kind described are customarily around the sheaves 21., as best shown in Fig. 3. The suspender structure usually includes an elastic element or, at any rate, is so designed that there will be an upward tension maintained on 7, the ankle joint pivot involves a sleeve 33 that is set into or against the solid portion l3 of the lower leg section II and is anchored thereto by nut-equipped bolt-like extensions 34. Working within the sleeve 33 is a shaft 35 between which and the sleeve 33 wire-like rollers 36 are preferably interposed. Working through segmental --slots 31 in the sleeve 33, and having threaded the suspending cords 28; and this upward strain or tension will tend to impart a forward swinging movement to the lower leg section, or in the walking action, the foot is released from pressure on the ground. That thisiaction willtake place will appear evident by noting in Fig. 3, for example, the fact that the cordsare brought rearward and back of the axis of the knee joint pivot.

The forward and rearward movements of the lower leg section in respect, to the .upper leg section is limited by engagement of the stop pin or bolt 24 with the extreme ends of the slot 23. To cushion the movements of the lower leg section, leather or other pliable, buffers 23 are preferably inserted at, theends of the,slo t 2 3. In fact, the ends of the.slot.23 or the. buffers, 23 form limiting stops that areoffset from the axis of the knee joint and are circumferentially spaced. The segmental slot, howevenin addition to performing the functionofa stop means, serves as a sort of guide device. forgiving, the leg structure lateral stability. It will ,be noted that the sides of the hub flanges. l4 quite closely engage the inner faces of ,thesheaves 21 and keepthe latter pressed against theme-tallic hinge straps l9.

V The sheaves 22 and 2,1, and especially the latter, permit the straps .28, that freedom of endwise movement that is required tojipreventyslipping of the shoulder straps on the wearer when, for example, the person wearingthe leg'sits down and permits the lower leg section to move pivotal 1y backward or toward a, positionindicatedgby dotted lines on Fig. 4.

Some persons Wearinglegs of. this. general character find it necessary or desirable to walk with stiff knee joint; hence, 11' provide; a lock device preferably in the nature .of a sliding lock bolt which may be readily movedfrominopera tive position to operative position to lock the leg structure against movement at the knee joint. This device, as shown in the drawings, involves a lock bolt mounted to slide vertically through the hub flange I4 from an inoperative position shown by dotted lines on Fig. 4, into an operative position shown by'full lines, and in which latter position, the lower end of saidlock bolt will engage back of the stop bolt or rod 24 and ends with adjustable nuts 40. passed freely through clamping bars 4| and 42.

- -engagement with the shaft and projecting radially therefrom, are trunnions 38 provided with stud-like-projections 39 equipped at their lower Studs 39 are By reference particularly to Fig. 2 it will be noted that when applied to the foot l2,.the studs 39 are passed through a web [2, in the heel ofthe foot and that when nuts 401are tightened, 'the bars 4| and 42 will be clamped tightly against'the web I2'.. The nuts 40 and lower bars 42 are countersunk int'o' theholeiof the foot. With this arrangement the nuts 40, can be tightened to any desired extent without in any way varying the frictional contact between the sleeve 33 and the shaft '35. As further shown in Fig.1 2, the numeral 43 indicates a heel spring applied'between the heel of the foot and "the solid lower endof the lower leg section. The numeral 44, indicates a stop forv limiting the hinge movement of'the These 'ele ments 43 and 44, however, are not per se features of the present invention.

This improved leg has been put into commercial use and has been found highly eflicient for the purposes had in view; "It has few partsand in fact has no parts that require frequent ',ad-'

justment. The stop elements for limiting the movements of the lower leg section inrespct to the upper leg section are solidly connected one to the upper leg section,'and the other to the are adjustments if once prop comprising lower and lupper leg sections, metallic hinge straps secured ;to the upper side portions of said lower leg section, said upper leg section having a segmental hub flange located between the upper ends of said hinge straps, a knee hinge bolt extended through the hub flange of said upper section and at itsends anchored to the upper portions of said hinge straps, a stop bolt located directly below said knee joint hinge bolt and at its ends-anchored to said hinge straps, said hub flange having cirlock the knee joint against movement. Lock bolt In many and probably most of 1,405,191. As shown in the drawings Figs.-2, and

cumferentially spaced stop elements engageable with said stop bolt to limit the swinging movements of said lower leg section in respect to said upper leg section, and shoulder straps extended in front of said knee hinge bolt and around and under said stop bolt,said shoulder straps, under upward tension, serving to cause said lower leg section to swing forward in respect to said upper leg section, in furthercombination with alock bolt mounted in the upper leg section for movement through the hub flange thereof into a position to engage said stop bolt and lock the lower to the lower leg section...

leg section against-pivotalmovement in respect oTro H. ERIcKs'oiI. 

